drm/amd/display: Delete disp_clk_voltage from integrated info (v2)

drm/amd/display: Delete disp_clk_voltage from integrated info (v2)

Only DCE 11.0 relies on this information and even that
didn't use this field, because it queries the information
from the pplib. It also filled the field incorrectly on
that version.

On newer GPUs, the VIOS integrated info no longer contains
display clock voltage dependencies, so we don't need it.

v2:
- Also delete some code wrapped in #if 0

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>